Project Summary Despite major public health efforts, auto crashes remain by far the leading cause of death among 16-19 year-olds and are a major cause of non-fatal injuries. There is a clear, ongoing need to identify unaddressed, reversible conditions that increase risk for adolescent drivers. We propose that obstructive sleep apnea (OSA) is an under-recognized, treatable condition that worsens driving skills in adolescents by inducing sleepiness and inattention. Suggestive evidence converges from studies of (a) crash risk in adults with OSA, (b) neurobehavioral functioning in youth with OSA, and (c) neurobehavioral and driving skills in sleep-deprived adolescents. If our hypotheses are correct, documenting and addressing the effect of adolescent OSA on driving skills could improve OSA care and prevent thousands of crash-related injuries and deaths every year. However, evidence remains circumstantial and it is questionable to generalize findings from research on highly-experienced middle-aged adult drivers to inexperienced adolescent drivers, for whom the act of driving places much greater demands on vigilance and divided attention. Our long-term plan is to conduct a detailed on-road study which could definitively speak to the driving-related risk and reversibility of adolescent OSA. Before making that investment of time and resources, we first must clearly show driving skill deficits in a sample of rigorously-diagnosed adolescents with and without OSA in a controlled setting that allows for sensitive measurement of effects and ethical presentation of driving challenges. The proposed small-scale study will accomplish those critical first steps, while also providing key guidance on likely mechanisms of effect. Thirty 16-19-year-old drivers with untreated OSA and thirty OSA-free controls will undergo driving simulation of a nature that is sensitive to OSA in adults and to sleep restriction in teens. Our first aim is to test whether adolescent OSA increases driving risk. Compared to controls, we expect that that adolescents with OSA will have more difficulty maintaining their lanes in the simulator, as well as more protracted eye glances from the roadway when engaged in a text messaging conversation. Our second aim is to test whether inattention and daytime sleepiness are key mechanism in inducing OSA-linked driving risk. This novel study will be the first to test the presence and mechanisms underlying driving skill deficits in youth with OSA. It capitalizes on the unique equipment available at Cincinnati Children's and the unique expertise of our research team, which includes experts in adolescent sleep pathology, neurobehavioral assessment, adolescent attention, driving simulation, statistical analyses, and generalization to real-world driving settings. While quite treatable, adolescent OSA is rarely detected, let alone treated. If our hypotheses are correct, this study will open new opportunities to improve the health and safety of young drivers with currently undetected OSA, as well as the millions more with whom they share the road.